usr/src/lib/lvm/libmeta/common/metagetroot.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 /*
  30  * get root device
  31  */
  32
  33 #include <meta.h>
  34 #include "meta_lib_prv.h"
  35
  36 #include <sys/mnttab.h>
  37
  38 /*
  39  * Return the current root filesystem block device name
  40  */
  41 void *
  42 meta_get_current_root(
  43         md_error_t      *ep
  44 )
  45 {
  46         FILE            *fp;
  47         struct mnttab   mp;
  48
  49         if ((fp = open_mnttab()) == NULL) {
  50                 (void) mdsyserror(ep, errno, MNTTAB);
  51                 return (NULL);
  52         }
  53
  54         while (getmntent(fp, &mp) == 0) {
  55         if (strcmp(mp.mnt_mountp, "/") == 0)
  56                 return (mp.mnt_special);
  57         }
  58         (void) mderror(ep, MDE_NOROOT, NULL);
  59         return (NULL);
  60 }
  61
  62 /*
  63  * Return the current root filesystem block device name. This is only valid
  64  * when root is either a slice, a stripe or a mirror.
  65  */
  66 mdname_t *
  67 meta_get_current_root_dev(
  68         mdsetname_t     *sp,
  69         md_error_t      *ep
  70 )
  71 {
  72         md_stripe_t     *stripep;
  73         md_mirror_t     *mirrorp;
  74         md_row_t        *rp;
  75         md_comp_t       *cp;
  76         mdname_t        *rootnp;
  77         void            *curroot;
  78         char            *miscname;
  79         int             smi;
  80
  81         if ((curroot = meta_get_current_root(ep)) == NULL)
  82                 return (NULL);
  83         if ((rootnp = metaname(&sp, curroot, UNKNOWN, ep)) == NULL)
  84                 return (NULL);
  85         if (metaismeta(rootnp)) {
  86                 if ((miscname = metagetmiscname(rootnp, ep)) == NULL)
  87                         return (NULL);
  88                 if ((strcmp(miscname, MD_MIRROR) == 0) &&
  89                     ((mirrorp = meta_get_mirror(sp, rootnp, ep)) != NULL)) {
  90                         for (smi = 0; smi < NMIRROR; smi++) {
  91                                 md_submirror_t *mdsp =
  92                                     &mirrorp->submirrors[smi];
  93                                 rootnp = mdsp->submirnamep;
  94                                 /* skip unused submirrors */
  95                                 if (rootnp == NULL) {
  96                                         assert(mdsp->state == SMS_UNUSED);
  97                                         continue;
  98                                 }
  99                                 if ((miscname = metagetmiscname(rootnp, ep))
 100                                     == NULL) {
 101                                         (void) mdmderror(ep, MDE_UNKNOWN_TYPE,
 102                                             meta_getminor(rootnp->dev),
 103                                             rootnp->cname);
 104                                         return (NULL);
 105                                 }
 106                                 break;
 107                         }
 108                 }
 109                 if ((strcmp(miscname, MD_STRIPE) == 0) &&
 110                     ((stripep = meta_get_stripe(sp, rootnp, ep)) != NULL)) {
 111                         rp = &stripep->rows.rows_val[0];
 112                         cp = &rp->comps.comps_val[0];
 113                         if (metachkcomp(cp->compnamep, ep) == 0)
 114                                 return (cp->compnamep);
 115                 }
 116                 /* Root is not a single stripe metadevice */
 117                 (void) mddeverror(ep, MDE_INV_ROOT, rootnp->dev, rootnp->cname);
 118                 return (NULL);
 119         } else return (rootnp);
 120 }